American Journal of Applied Sciences

Influences of Short Discrete Fibers in High Strength Concrete with Very Coarse Sand

Mahyuddin Ramli and Kwan Wai Hoe

DOI : 10.3844/ajassp.2010.1572.1578

American Journal of Applied Sciences

Volume 7, Issue 12

Pages 1572-1578

Abstract

Problem statement: High Strength Concrete (HSC) normally content high cementitous
amount and low water binder ratio. However, these would cause substantial volume changes to the
concrete and therefore affected the strength development. In addition, the brittleness of HSC was
increased when silica fume used as partial cement replacement to achieve high strength. Approach:
This study discussed the effects of incorporated short discrete Coconut Fibers (CF), Barchip Fibers
(BF) and Glass Fibers (GF) into HSC to enhance the performance of concrete while kept the binder
content at moderate level. Additional specialty to this HSC was casted with very coarse sand with
fineness modulus of 3.98. A total of thirteen mixes were casted and tested for slump, density,
compressive strength, flexural strength and ultrasonic pulse velocity in accordance with British
Standards. Results: The slump was slightly reduced by the short discrete fibers. All of the fibrous
specimens had lower density than control. However, the compressive strength of the HSC had
increased from 71.8-79.0 MPa using 1.8% of BF, while flexural strength had increased from 5.21-6.50
MPa. All specimens showed that ultrasonic velocity higher than 4.28 km sec-1.
Conclusion/Recommendations: In short, combination of incorporated short discrete fibers and
applied very coarse sand to produce HSC showed very satisfying results and improvements. Further
assessment on durability and impact resistivity will be verified in the coming research.